Flower Development in Walnut: Altering the Flowering Pattern by Gibberellic Acid Application

Abstract

The pattern of walnut flowering varies depending on genetic and environmental factors. To study the patterns of walnut pistillate flowers developing as a result of applying gibberellic acid (GA 3 ), the research was conducted as a factorial design with 2 factors (three levels of trunk diameter (10 to 12 cm, 12 to 14 cm and 14 to 16 cm) and four levels of GA 3 (0, 50,100 and 200 mg/l)) on 'Chandler' commercial cultivar. Different levels of GA 3 were sprayed twice on the trees, i.e. 2 and 4 weeks after flowering. A new method was used to study the pistillate flower development based on hand-cut cross sections of bud and staining with methyl blue and carmine. Based on the results, different development stages included induction; initiation and differentiation of the pistillate flower bud were observed respectively in late May, early June, September and March. The results of GA 3 application showed that GA 3 treatment can alter the flowering pattern of walnut. GA 3 application significantly increased the number of male flowers, total flowers, and male: female flower ratio per branch. The number of female flowers increased by increasing the tree trunk diameter. The highest number of female flowers (62.3) was observed in trees with trunk diameters between 14-16 cm and application of 100 mg/l of GA 3 . Linear regression analysis showed a positive and strong relation between truck diameter with total flower number as well as female flower number.

The long-term response of photosynthesis in walnut (Juglans regia L.) leaf to a leaf-to-fruit ratio

“…'Xinxin2' are relatively rich in natural conditions, which provides an opportunity to test the hypothesis proposed in this paper. According to literature, there were many studies on walnuts, such as walnut flowering (Hassankhah et al 2018), bud dormancy (Gholizadeh et al 2017), ex vitro acclimation of walnut plantlets (Maleki Asayesh et al 2017a,b), etc. Previous studies showed that photosynthesis of walnut leaves was affected by many factors, including kaolin (Rosati et al 2007, Gharaghani et al 2018, rootstock varieties (Li et al 2017), fertilizers (Nicodemus et al 2008, Liu et al 2010), acclimation (Chenevard et al 1997, light (Dean et al 1982, Atanasova et al 2003, salinity (Zhang et al 2002), and water (Scartazza et al 2001).…”

Identification and characterization of NF-Y gene family in walnut (Juglans regia L.)

“…The wood and fruit of walnut ( J. regia L.) are highly valuable, and the research of walnut focus on molecular breeding and flowering in recent years [ 60 – 65 ]. However, less attention were paid to walnut compare with other plants, because it must grow for many years before it becomes productive.…”

Flowering in Persian walnut: patterns of gene expression during flower development

“…The buds were sampled throughout the year with 14-day intervals and were fixed overnight in fixation solution (including 10% formaldehyde + 5% acetic acid + 50% ethanol). The buds were cut vertically with a sharp razor and were stained with methylene blue and carmine [61]. The microscopy technique (Nikon Eclipse E200, Japan) was used for the determination of flower development stage.…”